Keep in mind that keys are case sensitive (i.e. give "email" instead of "Email" and you get warning). Also remember it's important to keep the order of the arguments in array. Move the "Email" above commonName and check what you get (in case you don't know how: "openssl req -noout -text -in out.csr").

It also happened to me me I got segfault when order was rubbish (afair Email after countryName, or plenty Email's here and there), so be awared.